1. Field of the Invention
The invention relates to a light emitting device and a display panel. More particularly, the invention relates to a light emitting device and a display panel which can improve the light emission amount of a device.
2. Description of Related Art
An organic electroluminescent device is a semiconductor device capable of efficiently converting electrical energy into optical energy, and the organic electroluminescent device often serves as a light emitting device of indicator light, a display panel, and an optical pickup head. Since the organic electroluminescent device is characterized by the absence of viewing-angle dependence, simple manufacturing process, low costs, high response speed, wide operating temperature range, and full-color display, the organic electroluminescent device satisfying the requirement for the multi-media display is likely to become a mainstream of the next generation flat panel display.
In general, the organic electroluminescent device includes an anode, an organic light emitting layer, and a cathode. The organic electroluminescent device emits light by injecting holes and electrons into the organic electroluminescent layer respectively through the anode and the cathode. The electrons and the holes are re-combined in the organic electroluminescent layer to form photons, such that light is emitted.
The organic electroluminescent layer and a transparent conductive layer that acts as an electrode are both made of a material having a high refractive index. When the electrons and the holes are re-combined to produce light, parts of the light are refracted to generate incident light having a wide angle. Thereby, total reflection occurs at an interface between the transparent conductive layer and a substrate or at an interface between the substrate and the air, and the light emission amount is insufficient because the light is not able to be transmitted out.